High temperature superconductor systems in which a YBa.sub.2 Cu.sub.3 O.sub.7 layer with a c-axis crystal orientation with copper oxide planes parallel to the substrate surface are of interest for current transport at especially high current densities. For this purpose, the YBa.sub.2 Cu.sub.3 O.sub.7 layer can be grown with a c-axis orientation.
There are various processes known for effecting the growth of YBa.sub.2 Cu.sub.3 O.sub.7 layers with a c-axis orientation on an appropriate substrate. For example, high pressure dc sputtering can be used to deposit the YBa.sub.2 Cu.sub.3 O.sub.7 layers with a c-axis orientation. The type of crystal grown depends upon geometric conditions, pressure of the sputtering gas, furnace temperature and substrate temperature, choice of substrate and of sputtering gas and the current density during the sputtering.
However, even with an optimum choice of all of these parameters in prior systems, it has been found that with increasing layer thicknesses, the growth of a-axis crystal oriented regions cannot be avoided.
Once c-axis crystal oriented regions arise, they increasingly prevent uniform a-axis oriented growth. Until now there has been no solution to this problem.